Wafer level packaging method

ABSTRACT

A wafer level packaging method entails providing electronic devices and providing a platform structure having cavities extending through the platform structure. The platform structure is mounted to a temporary support. One or more electronic devices are placed in the cavities with an active side of each electronic device facing the temporary support. The platform structure and the electronic devices are encapsulated in an encapsulation material to produce a panel assembly. Redistribution layers may be formed over the panel assembly, after which the panel assembly may be separated into a plurality of integrated electronic packages. The platform structure may be formed from a semiconductor material, and platform segments within each package provide a fan-out region for conductive interconnects, as well as provide a platform for a metallization layer and/or for forming through silicon vias.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to integrated electronicpackages. More specifically, the present invention relates to waferlevel packaging for integrated electronic packages.

BACKGROUND OF THE INVENTION

Semiconductor and other types of electronic devices are commonlyencapsulated wholly or partly in plastic resin (i.e., mold compound) toform an integrated electronic package (also referred to as an integratedcircuit, IC, chip, or microchip). The plastic resin encapsulationmaterial provides environmental protection and facilitates connectionbetween such integrated electronic packages and external circuits.Electrical contacts for connection with external circuits are exposed atan exterior surface of an integrated electronic package and areconnected internally with electrical contact pads on a semiconductorchip or die within the package. Various techniques are available forinternally connecting the embedded electronic devices with the exposedelectrical contacts of the integrated electronic package.

One technique for connecting the exposed electrical contacts withelectrical contact pads on, for example, a semiconductor die entailstemporarily placing singulated semiconductor dies with their active sideon a support. The dies are embedded with a molding compound to form acomparatively flat or planar panel assembly, which is subsequentlyreleased from the temporary support. The contact pads on thesemiconductor die surfaces are then connected to exposed pads on theexterior surface of the panel assembly by a redistribution process toappropriately route the signal connections, and the power and groundconnections. The redistribution process (also referred to as a buildupprocess) includes deposition of a plurality of electrically conductivelayers by electroplating techniques and patterning using batch processlithography. The electrically conductive layers are separated byinsulating layers.

In certain types of electronic device packaging, a problem, referred toas “warping,” can occur during the encapsulation and formation of thepanel assembly. If the panel assembly has warped during encapsulation,the process of adding the electrically conductive layers using theredistribution process can be adversely affected, thereby reducingoverall yield and increasing manufacturing costs. As such, control orelimination of warping is important to achieving high manufacturingyields and low manufacturing costs in such encapsulated planarassemblies.

An embedded ground plane (EGP) is sometimes built into a panel assembly.The EGP is used to limit warpage of the panel assembly, control diedrift, and can also be used to provide a single routing option forground in a finished semiconductor package. Typically, such EGP's arefabricated from copper. Unfortunately, the use of a copper EGP can leadto relatively high manufacturing and tooling costs, undesirably highrate of saw blade wear during package singulation due to materialhardness, and high thermal expansion.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention may be derived byreferring to the detailed description and claims when considered inconnection with the Figures, wherein like reference numbers refer tosimilar items throughout the Figures, the Figures are not necessarilydrawn to scale, and:

FIG. 1 shows a cross-sectional side view of an integrated electronicpackage in accordance with an embodiment;

FIG. 2 shows a cross-sectional side view of an integrated electronicpackage in accordance with another embodiment;

FIG. 3 shows a cross-sectional side view of an integrated electronicpackage in accordance with another embodiment;

FIG. 4 shows a cross-sectional side view of a stacked integratedelectronic package in accordance with yet another embodiment;

FIG. 5 shows a top view of a panel assembly that includes a platformstructure and multiple electronic devices;

FIG. 6 shows a top view of a panel assembly that includes anotherplatform structure and multiple electronic devices;

FIG. 7 shows a flowchart of a wafer level packaging process inaccordance with another embodiment;

FIG. 8 shows a simplified perspective view exemplifying a structure atan initial stage of the wafer level packaging process of FIG. 7;

FIG. 9 shows a simplified perspective view exemplifying a structure at asubsequent stage of the wafer level packaging process;

FIG. 10 shows a simplified perspective view exemplifying a structure ata subsequent stage of the wafer level packaging process;

FIG. 11 shows a simplified perspective view exemplifying a structure ata subsequent stage of the wafer level packaging process;

FIG. 12 shows a side view of the structure of FIG. 11 along sectionlines 12-12 shown in FIG. 11;

FIG. 13 shows a simplified perspective view exemplifying a structure ata subsequent stage of the wafer level packaging process;

FIG. 14 shows a partial side view of the structure of FIG. 13;

FIG. 15 shows a simplified perspective view of a panel assembly formedin accordance with the wafer level packaging process;

FIG. 16 shows a partial side view of the panel assembly of FIG. 15 at asubsequent stage of processing;

FIG. 17 shows a partial side view of the panel assembly from FIG. 16 ata subsequent stage of processing;

FIG. 18 shows a partial side view of the panel assembly from FIG. 17 ata subsequent stage of processing;

FIG. 19 shows a partial side view of the panel assembly from FIG. 18 ata subsequent stage of processing; and

FIG. 20 shows a partial side view of the panel assembly from FIG. 19 ata subsequent stage of processing.

DETAILED DESCRIPTION

A method of wafer level packaging and integrated electronic packagesproduced via the wafer level packaging methodology are provided. Moreparticularly, a panel assembly of electronic devices is fabricated thatincludes an embedded platform structure formed of a semiconductormaterial. The embedded platform structure serves to limit warpage of thepanel assembly during encapsulation relative to a panel assembly made ofmold compound in order to increase package yield and decreasemanufacturing complexity during a subsequent build up process.Furthermore, the incorporation of a platform structure, such as asilicon wafer, can reduce material costs as well as manufacturing andtooling costs, and can reduce saw blade wear rate during packagesingulation relative to the use of a copper EGP. Additionally, theimplementation of an embedded platform structure, such as asemiconductor wafer, in the panel assembly can achieve reduced thermalexpansion, hence better die drift performance, relative to the use of acopper EGP. And still further, the platform structure embedded in thepanel assembly can be used as a platform for additional electroniccircuits and/or for forming through silicon vias.

FIG. 1 shows a cross-sectional side view of an integrated electronicpackage 20 in accordance with an embodiment. Integrated electronicpackage 20 includes a platform segment 22 having a cavity 24 extendingthrough platform segment 22. Integrated electronic package 20 furtherincludes an electronic device 26 and encapsulation material 28 residingin cavity 24. Encapsulation material 28 fills cavity 24 and coupleselectronic device 26 to platform segment 22.

In the illustrated configuration, platform segment 22 has a firstsurface 30, and a second surface 32, opposing first surface 30.Electronic device 26 has an active side 34 and a back side 36 opposingactive side 34. Electrical contacts 38 are located at active side 34 ofelectronic device 26. In general, active side 34 of electronic device 26and electrical contacts 38 are approximately coplanar with first surface30 of platform segment 22. Electrical contacts 38 are shown extendingabove active side 34 of electronic device 26 for visibility in theillustrated configuration of FIG. 1. Electrical contacts 38 need notextend above active side 34, but may instead be coplanar with activeside 34. The terms “first,” “second,” and so forth are used fordistinguishing between similar elements and not necessarily fordescribing a particular sequential or chronological order.

Active side 34 of electronic device 26 having electrical contacts 38(i.e., bond pads) are exposed from encapsulation material 28.Additionally, first and second surfaces 30, 32 of platform segment 22are exposed from encapsulation material 28. Likewise, portions 40 ofplatform segment 22 are exposed from encapsulation material 28 atopposing side walls 42, 44 of integrated electronic package 20.

Typically, a semiconductor wafer is used in the fabrication ofintegrated circuits and other microdevices. The wafer typically servesas the substrate for microelectronic devices built in and over thesemiconductor wafer. In accordance with an embodiment, platform segment22 is a portion of a semiconductor wafer that serves in an anti-warpagecapacity during fabrication. That is, platform segment 22 is preferablyformed from a semiconductor material having a coefficient of thermalexpansion (CTE) of approximately 10 ppm/° C. (parts-per-million perdegree centigrade) or less, and that contains particles or grains ofaround five microns or less in size. In some embodiments, platformsegment 22 may be formed from a silicon crystal semiconductor wafer.However, alternative semiconductor materials may be utilized to formplatform segment 22. These alternative semiconductor materials include,for example, indium antimonide, indium arsenide, gallium antimonide,indium phosphide, gallium arsenide, gallium nitride, germanium, galliumphosphide, silicon carbide, and other crystalline materials suitable foruse in the electronics industry.

Thermal expansion is the tendency of matter to change in volume inresponse to a change in temperature through heat transfer. The CTE isdefined as the degree of expansion divided by the change in temperature.A prior art copper EGP has a relatively high CTE of about 16.6 ppm/° C.,whereas, silicon has a CTE of about 2.6-3.5 ppm/° C., and encapsulationmaterial 28 has a CTE of about 10 ppm/° C. An arrangement that includesplatform segment 22 formed from silicon in lieu of some of theencapsulation material 28 in integrated electronic package 20 achieves asignificantly lower CTE than prior art designs. A lower CTE can limitwarpage of the semiconductor wafer during fabrication, as will bediscussed below.

Platform segment 22 exhibits a thickness 46 between first and secondsurfaces 30, 32. In some embodiments, the semiconductor wafer used toproduce platform segment 22 is selected to have thickness 46 that is atleast equivalent to a height 48 of electronic device 26 between activeside 34 and back side 36. Thickness 46 is sufficient to providestiffening capability in a panel assembly in order to control panelwarpage during the manufacture of package 20, as will be discussed ingreater detail below. In the illustrated embodiment, thickness 46 isgreater than height 48 of electronic device 26. Accordingly, back side36 of electronic device 26 is embedded in encapsulation material 28 tosecure device 26 to platform segment 22 and to provide environmentalprotection to electronic device 26. In alternative embodiments, however,electronic device 26 may be thicker than platform segment 22. In such acase, second surface 32 of platform segment 22 may be embedded inencapsulation material.

Due to its material composition (e.g., semiconductor material), platformsegment 22 may also include a metallization layer 50 formed directly ona non-cavity area 52 of platform segment 22, in order to gain greaterefficiencies in scale and device complexity of integrated electronicpackage 20. In the illustrated example, metallization layer 50 is formedon first surface 30 of platform segment 22 as an M0 (metal zero) layerand may encompass one or more conductive traces in accordance with aparticular design. However, some embodiments may additionally oralternatively include integrated circuits formed directly on thesemiconductor material.

Electronic device 26 is generally any type of electronic device that mayor may not be in chip form. Accordingly, such other types of devicesincluding the non-limiting examples given below, are intended to beincluded in the terms “device,” “electronic device,” “electroniccircuitry” whether singular or plural. Furthermore the terms “device,”“die, and “chip” are intended to be substantially equivalent.Non-limiting examples of suitable devices are semiconductor integratedcircuits, individual semiconductor devices, piezoelectric devices,magnetoresistive devices, solid state filters, magnetic tunnelingstructures, integrated passive devices such as capacitors, resistors andinductors, electrical interconnects, and combinations and arrays of anyand all of these types of devices and elements. Further, the presentinvention does not depend upon the types of die or chips or devicesbeing used. Nor does the present invention depend upon the materials ofwhich the die or chips or devices are constructed provided that suchmaterials can withstand the encapsulation and subsequent buildupprocesses.

With continued reference to FIG. 1, electrical interconnects 54 extendfrom electrical contacts 38 on active side 34 of electronic device 26 toconductive elements 56 exposed on an exterior surface 58 of integratedelectronic package 20. More particularly, electrical interconnects 54may be formed from an electrically conductive layer 60 suitablypatterned to produce traces 62 and vias 64 that extend through a layeredarrangement of insulating dielectric layers 66, 68 to interconnect withconductive elements 56, which may be solder balls, at exterior surface58 of integrated electronic package 20.

Patterning of electrically conductive layer 60 (sometimes referred to asa metal layer or a metallization layer) to produce traces 62 and vias 64enables an array or arrays of electrical contacts 38 on active side 34of electronic device 26 to be redistributed geometrically, so that thearray of conductive elements 56 at exterior surface 58 may have adifferent geometry from the geometry of electrical contacts 38 onelectronic device 26. In this example, exterior surface 58 of integratedelectronic package 20 is the exposed exterior of the outermostdielectric layer, i.e., dielectric layer 68.

It should be noted that conductive elements 56 are not necessarilydirectly aligned with electrical contacts 38, and may instead bedisplaced laterally so that traces 62, vias 64, and/or conductiveelements 56 are aligned with (i.e., underlie or overlie) non-cavity area52 of platform segment 22. As shown in FIG. 1, integrated electronicpackage 20 is formed utilizing a packaging technique that enables afan-out design (i.e., redistribution) of conductive elements 56 andinterconnect routing.

Only one cavity 24 and one electronic device 26 are shown in FIG. 1 forsimplicity of illustration. Additionally, the exemplary integratedelectronic package 20 shown in FIG. 1 and the integrated electronicpackages shown in FIGS. 2-4 include only a few electrical contacts,conductive elements, electrical interconnects, and dielectric layers forsimplicity of illustration. It should be appreciated that an integratedelectronic package, such as those illustrated herein, may include anycombination and quantity of cavities 24 and electronic devices 26 andany combination of electrical contacts, conductive elements, electricalinterconnects, and dielectric layers in accordance with a particulardevice design.

FIG. 2 shows a cross-sectional side view of an integrated electronicpackage 70 in accordance with another embodiment. Integrated electronicpackage 70 can include components similar to those described inconnection with integrated electronic package 20 (FIG. 1). For example,integrated electronic package 70 includes platform segment 22 and cavity24 extending through platform segment 22. However, this example includesmultiple electronic devices 72, 74, 76 residing in cavity 24 andembedded in encapsulation material 28. Additionally, integratedelectronic package 70 can include corresponding electrical contacts 38on electronic devices 72, 74, 76, conductive elements 56 exposed onexterior surface 58 of integrated electronic package 70, and electricalinterconnects 54 routed through dielectric layers 66, 68. Accordingly,the example of FIG. 2 is provided to demonstrate that cavity 24 caninclude more than one electronic device along with associated electricalcontacts, conductive elements, and electrical interconnects inaccordance with a particular device design.

FIG. 3 shows a cross-sectional side view of an integrated electronicpackage 80 in accordance with another embodiment. Integrated electronicpackage 80 includes platform segment 22 having multiple cavities 82, 84,86 extending through platform segment 22. In this example, electronicdevice 72 resides in cavity 82, electronic device 74 resides in cavity84, and electronic device 76 resides in cavity 86. Additionally,integrated electronic package 80 can include corresponding electricalcontacts 38 on electronic devices 74, 76, conductive elements 56 exposedon exterior surface 58 of integrated electronic package 80, andelectrical interconnects 54 routed through dielectric layers 66, 68.

With continued reference to FIG. 3, integrated electronic package 80further includes through-silicon vias (TSV) 88 and a through-package via(TPV) 90. Each of TSV 88 and TPV 90 extend through platform segment 22to conductive interconnects 92. Conductive interconnects 92 are formedfrom an electrically conductive layer 94 that is suitably patterned toproduce traces 96 and vias 98 that extend through a layered arrangementof insulating dielectric layers 100, 102 to interconnect with conductiveelements 104 (e.g., surface mount elements) at an exterior surface 106,opposing exterior surface 58, of integrated electronic package 80. Inthis example, exterior surface 106 of integrated electronic package 80is the exposed exterior of the outermost dielectric layer, i.e.,dielectric layer 102.

TSV 88 and TPV 90 are considered complementary three dimensionalpackaging enablers, where TSV 88 enables fine geometry (for example,approximately ten micron diameter) and TPV 90 enables coarse geometry(for example, approximately one hundred to two hundred micron diameter).TSV 88 is a vertical electrical connection (where the term “via”typically refers to Vertical Interconnect Access) passing completelythrough platform segment 22. Typical uses for TSV 88 includethree-dimensional die stacking, high input/output, and high bandwidthapplications. TPV 90 is also a vertical electrical connection passingbetween or passing completely through one or more integrated electronicpackages. TPV 90 can replace conventional edge wiring when creatingthree dimensional packages as well as providing for double-side mountingactive circuits, logic, and memory in order to reduce package size.Typical uses for TPV 90 include three-dimensional system in package(SiP) and true heterogeneous integration applications.

Accordingly, the example of FIG. 3 is provided to demonstrate that anintegrated electronic package can include multiple cavities each housingtheir respective electronic devices. The example of FIG. 3 is furtherprovided to demonstrate that the material properties of platform segment22 enable the inclusion of TSVs 88 and/or TPVs 90 and additional buildup layers for three-dimensional applications.

FIG. 4 shows a cross-sectional side view of a stacked integratedelectronic package 110 in accordance with yet another embodiment.Integrated electronic package 110 represents a three-dimensional packagein which integrated electronic package 20 and another integratedelectronic package 112 are bonded to form a stacked configuration.Integrated electronic package 112 includes a platform segment 114 havingat least one cavity 116 (of which only one is shown) extending throughsegment 114. Integrated electronic package 112 further includes at leastone electronic device 118 (of which only one is shown) residing incavity 116. Encapsulation material 120 fills cavity 116 and coupleselectronic device 118 to platform segment 114.

In the illustrated configuration, platform segment 114 has a firstsurface 122 and a second surface 124, opposing bottom surface 122.Electronic device 118 has an active side 126 and a back side 128opposing active side 126. Electrical contacts 130 are located at activeside 126 of electronic device 118. In general, active side 126 ofelectronic device 118 is approximately coplanar with bottom surface 122of platform segment 114.

Active side 126 of electronic device 118 having electrical contacts 130(e.g., bond pads) are exposed from encapsulation material 120.Additionally, bottom and top surfaces 122, 124 of platform segment 114are exposed from encapsulation material 120. Likewise, portions 132 ofplatform segment 114 are exposed from encapsulation material 120 atopposing side walls 134, 136 of integrated electronic package 112.

Conductive interconnects 138 extend from electrical contacts 130 onactive side 126 of electronic device 118 through a layered arrangementof insulating dielectric layers 140, 142 formed over active side 126 ofelectronic device 118 and bottom surface 122 of platform segment 114. Inthe example of FIG. 4, at least one of conductive interconnects 138extends to side wall 136 of integrated electronic package 112.Similarly, for integrated electronic package 20, at least one ofelectrical interconnects 54 extends to side wall 44 of package 20. Aconductive trace 144 is formed extending along side wall 44. Conductivetrace 144 is coupled between electrical interconnect 54 at side wall 44of integrated electronic package 20 and conductive interconnect 138 atside wall 136 of integrated electronic package 112 so as to electricallyinterconnect conductive trace 144 with electronic device 118. In such amanner, electronic device 26 of package 20 may be suitably electricallyconnected with electronic device 118 in accordance with a particularpackage design.

The exposed portions of respective platform segments 22 and 114, andmore specifically, side walls 44 and 136, formed from a semiconductormaterial are significantly smoother than side walls formed fromencapsulation material. This smoother surface enables more durableadhesion of conductive trace material 144 to exposed portions 40 and 132of respective platform segments 22 and 114 than to prior art deviceshaving side walls of exposed encapsulation material, thereby increasingprocess yield as compared to these prior art devices having side wallsof exposed encapsulation material.

FIG. 5 shows a top view of a panel assembly 150 that includes a platformstructure, in the form of a semiconductor wafer 152, multiple electronicdevices 72, 74, 76 residing in multiple cavities 24, TSV 88 and TSV 90.In general, semiconductor wafer 152 is a grid structure of singlecrystal silicon that may be suitably processed to form cavities 24, TSV88 and/or TSV 90. However, the platform structure may alternatively beformed from another semiconductor material, some of which were listedabove. As shown for exemplary purposes, cavities 24 are sized toaccommodate placement of electronic devices 72, 74, 76. Panel assembly150 is not shown with encapsulation material 28 (FIG. 1) fillingcavities 24 so as to highlight the placement of electronic devices 72,74, and 76 within cavities 24.

Scribe lines 154, also known as saw streets, are demarcated onsemiconductor wafer 152 by dashed lines. Scribe lines 154 represent thenon-functional spacing on panel assembly 150 where a saw can safely cutpanel assembly 150 without damaging electronic devices 72, 74, 76.Following processing, panel assembly 150 containing semiconductor wafer152 is sawn, diced, drilled or otherwise separated to form a pluralityof integrated electronic packages (such as packages 20, 70, 80, and 110,each containing a semiconductor wafer segment as discussed in connectionwith FIGS. 1-4). In a prior art panel assembly in which the panel isformed (i.e., reconstituted) using encapsulation material (i.e., moldcompound), the width of the scribe lines is typically in the range of200-300 microns to accommodate encapsulation material tear off duringthe sawing or laser drilling operation. This is due to the encapsulationmaterial particulate size on the order of 30 to 50 microns and itscorresponding roughness. In contrast, a crystal silicon semiconductorwafer 152 has a particle or grain size around 5 microns. Thus, crystalsilicon semiconductor wafer 152 enables the width of scribe lines 154 tobe in the range of 30 to 40 microns. Narrower scribe lines 154 allowsfor a greater number of integrated electronic packages per panelassembly 150 as compared to prior art panel assemblies in which thepanel is formed (i.e., reconstituted) using encapsulation material(i.e., mold compound).

FIG. 6 shows a top view of a panel assembly 160 that includes anotherplatform structure, in the form of a semiconductor wafer 162, multipleelectronic devices 72, 74, 76 residing in multiple cavities 24, TSV 88and TSV 90. As discussed previously, the platform structure mayalternatively be formed from another semiconductor material. In theillustrated embodiment, metallization layer 50 is formed on a surface166 of semiconductor wafer 162. Metallization layer 50 can be anycombination of conductive traces, formed as an M0 (metal zero) layer onsemiconductor wafer 162. Metallization layer 50 is simplisticallyillustrated using lines and shaded rectangles. Those skilled in the artwill understand that the form and function of metallization layer 50 isdictated by a particular integrated electronic package design.

Semiconductor wafer 162 is a grid structure of single crystal siliconthat may be suitably processed to form cavities 24, TSV 88, and/or TSV90. Again cavities 24 are sized to accommodate placement of electronicdevices 72, 74, 76. However, in this example, cavities 24 have acurvilinear shape. That is, cavities 24 are characterized by a curvedline or path. More specifically in this example, cavities 24 aregenerally circular. The curvilinear shape of cavities 24 eliminatessharp corners in the single crystal silicon of semiconductor wafer 162,thereby reducing the potential for cracks forming during or followingfabrication operations associated with semiconductor wafer 162. Itshould be understood that cavities 24 may have other shapes thateliminate sharp corners, such as generally rectangular cavities withrounded inside corners.

FIG. 7 shows a flowchart of a wafer level packaging process 170 inaccordance with another embodiment. Wafer level packaging process 170can be implemented to fabricate any of integrated electronic packages20, 70, 80, 110 described in connection with FIGS. 1-4. Of course, waferlevel package process 170 may be executed to fabricate a plurality ofvariations of integrated electronic packages, each containing asemiconductor wafer segment.

Process 170 includes providing (172) electronic devices (e.g., 24, 72,74, 76 as discussed in connection with FIGS. 1-4), providing (174) orotherwise suitably processing a semiconductor wafer (e.g., 152 of FIG. 5or 162 of FIG. 6) with additional features (e.g., cavities 24, 82, 84,86, TSV 88 and/or TSV 90), and providing (176) a mold frame sized toaccommodate the semiconductor wafer. The mold frame and semiconductorwafer are mounted (178) to a temporary support with the semiconductorwafer residing in the mold frame, and the electronic devices are placed(180) with their active sides facing the temporary support.

The semiconductor wafer and the electronic devices residing in thecavities are encapsulated (182) in a mold compound (e.g., encapsulationmaterial 28, 120 as discussed in connection with FIGS. 1-4) to form a“reconstructed wafer” or panel assembly (e.g., 150, 160 as discussed inconnection with FIGS. 5 and 6). Any gaps between electronic deviceswithin each cavity and any gaps between the electronic devices and thesurrounding semiconductor wafer are filled with the mold compound. Themold compound is then at least partially cured. A backside grindoperation (184) may be performed to expose a surface of thesemiconductor wafer (e.g., second surface 32 as discussed in connectionwith FIGS. 1-4). The panel assembly can then be removed (186) from thetemporary support.

In an embodiment, one or more redistribution layers are formed (188) onthe panel assembly. At step 188, the panel assembly is mounted onto asupport carrier with the active side of the electronic devices orientedface up so that they are exposed. Formation of the redistribution layerscan entail forming an M0 (metal zero) metallization layer, a dielectriclayer over the exposed surface of the semiconductor wafer, the M0metallization layer, and the active side of the electronic devices(e.g., deposition), forming openings in the dielectric layer (e.g.,pattern) to the desired electrical contacts on the active side of theelectronic devices, and forming the conductive interconnects over thedielectric layer (e.g., sputter and plate).

Those skilled in the art will understand that more than one insulatinglayer, more than one set of openings, and more than one conductive layermay be required to achieve the desired interconnections of electricaldevices within the panel assembly. Thus, the above processes can berepeated as needed to get a desired layered arrangement of dielectriclayers and conductive interconnects. The dielectric layer(s) may bedeposited using any method which is compatible with fan-out wafer levelpackaging processing including, but not limited to, spin-coating,lamination, or printing. The fan-out wafer level packaging process iscompatible with a variety of dielectric deposition methods, and as such,embodiments are not limited by the method employed. Additionally, thefan-out wafer level packaging process is not dependent upon themethodology and materials used to form the conductive interconnects. Assuch, specific details will not be discussed herein for brevity.

In an embodiment, the package contacts (e.g., conductive elements 56 ofFIGS. 1-4) are applied (190) over the layered arrangement of dielectriclayers and conductive interconnects (i.e., the redistribution layers).The package contacts may be solder balls that are applied onto theexposed electrical contacts of the conductive interconnects usingautomated equipment. The panel assembly can then be separated (192) intoa plurality of integrated electronic packages. This can be done usingmethods known in the industry, for example, using any of a variety ofwafer sawing or dicing techniques. The now singulated integratedelectronic packages may be useful as-is and in such an embodiment waferlevel packaging process 170 can optionally proceed to END, asexemplified by a path 193.

Alternatively, process 170 can proceed in a further embodiment to form astacked integrated electronic package (e.g., package 110 of FIG. 4) bystacking and coupling (194) the electronic packages (e.g., integratedelectronic packages 20, 112 of FIG. 4). This is done using known bondingtechniques and materials. The stacked and coupled integrated electronicpackages may be useful as-is and in such an embodiment wafer levelpackaging process 170 can optionally proceed to END, as exemplified by apath 195.

Alternatively, process 170 can proceed in a further embodiment toelectrically interconnect electronic devices within each of theintegrated electronic packages to one another. That is, a conductivetrace (e.g., conductive trace 144 of FIG. 4) is formed (196) on one ofthe side walls of the stacked integrated electronic packages toelectrically interconnect certain electronic devices within each of theintegrated electronic packages. Thereafter, wafer level packagingprocess 170 proceeds to END. Of course, post processing may be performedfollowing step 196 including, for example, testing, attachment to aprinted circuit board, and so forth. The specific details of the postprocessing activities are not described herein for brevity.

The subsequent FIGS. 8-20 and the following description demonstratevarious operations that may be performed in connection with theexecution of wafer level packaging process 170 (FIG. 7). Hence, waferlevel packaging process 170 should be reviewed concurrent with thefollowing discussion of FIGS. 8-20.

FIG. 8 shows a simplified perspective view exemplifying a structure atan initial stage 198 of execution of wafer level packaging process 170.At initial stage, a tape 200 can be applied to a substrate 202. Tape 200is oriented so that an adhesive side is facing substrate 202. Adouble-sided tape 204 may be applied to tape 200. The combination ofsubstrate 202, tape 200, and double-sided tape 204 forms a temporarysupport 206. Substrate 202 may be glass ceramic, metal, or any othersuitable material. Adhesion to substrate 202 can be achieved usingthermal release tapes, silicone adhesives, or other temporary bondingmedia.

FIG. 9 shows a simplified perspective view exemplifying a structure at asubsequent stage 208 of wafer level packaging process 170, andparticularly at steps 176, 178 (FIG. 7). At stage 208, a mold frame 210may be mounted to temporary support 206. Additionally, a platformstructure such as a semiconductor wafer 212 is mounted to temporarysupport 206 within mold frame 210. Semiconductor wafer 212 is providedwith cavities 214, and can be provided with through-silicon vias 88, andthrough-package vias 90 (discussed in connection with FIGS. 1-4). Moldframe 210 and semiconductor wafer 212 adheres to double-sided tape 204of temporary support 206.

FIG. 10 shows a simplified perspective view exemplifying a structure ata subsequent stage 216 of wafer level packaging process 170. At stage216, semiconductor wafer 212 is shown mounted to temporary support 206within mold frame 210. Although a mold frame is described herein, itshould be understood that a mold frame may not be utilized in analternative packaging process. For example, semiconductor wafer 212 maybe mounted to temporary support 206, which can subsequently beencapsulated to fill cavities 214. In such a process, semiconductorwafer 212 would act as a type of mold frame, and would thus need to begreater than or equal to the height of the thickest electronic device tobe placed in cavities 214.

Referring to FIGS. 11-12, FIG. 11 shows a simplified perspective viewexemplifying a structure at a subsequent stage 218 of the wafer levelpackaging process 170, and more particularly at step 180 (FIG. 7), andFIG. 12 shows a side view of the structure of FIG. 11 along sectionlines 12-12 shown FIG. 11. At stage 218, electronic devices 220 areplaced in cavities 214 of semiconductor wafer 212. Electronic devices220 are placed in cavities 214 with an active side 222 of eachelectronic device 220 facing temporary support 206 and adhered todouble-sided silicon tape 204. Cavities 214 are sized to accommodateelectronic devices 220. However, gaps 224 may be located between deviceedges 226 of electronic devices 220 and wafer edges 228 of semiconductorwafer 212 (best seen in FIG. 12).

Referring to FIGS. 13-14, FIG. 13 shows a simplified perspective viewexemplifying a structure at a subsequent stage 230 of wafer levelpackaging process 170, and more particularly at step 182 (FIG. 7), andFIG. 14 shows a partial side view of the structure of FIG. 13. At stage230, an encapsulation material 232 (e.g., mold compound) can be appliedover a surface 234 of semiconductor wafer 212 and a back side 236 ofelectronic devices 220. Encapsulation material 232 desirably fills gaps224 to secure electronic devices 220 within cavities 214. In accordancewith known processes, encapsulation material 232 may be screen printedonto semiconductor wafer 212 and electronic devices 220. In accordancewith alternative processes, encapsulation material 232 may be appliedvia dispense technique injection molding, transfer molding, and thelike. After application, the encapsulation material 232 may undergo ade-voiding process to remove air at locations at which encapsulationmaterial 232 is absent. Thereafter, the structure includingencapsulation material 232 may be cured to partially hardenencapsulation material 232 to a state suitable for back side grinding inaccordance with backside grind step 184 of wafer level packaging process170 (FIG. 7).

With continued reference to FIG. 14 in connection with FIG. 15, FIG. 15shows a simplified perspective view of a panel assembly 238 formed inaccordance with wafer level packaging process 170. More particularly,FIG. 15 shows panel assembly 238 following backside grind step 184 (FIG.7) which exposes surface 234 of semiconductor wafer 212, and followingremoval of panel assembly 238 from temporary support 206 (FIG. 13) inaccordance with step 186 (FIG. 7). In some embodiments, mold frame 210(FIG. 13) may be removed from temporary support 206 and panel assembly238 may be back ground to a desired thickness so as to expose surface234 of semiconductor wafer 212. Note that even after backgrinding,cavities 214 remain filled such that electronic devices 220 remainembedded within encapsulation material 232. Thereafter, panel assembly238 may be released from glass substrate 202 and double-sided tape 204may then be peeled from panel assembly 238. Additional processing mayentail curing encapsulation material 232 by heating panel assembly 238,exposing panel assembly 238 to ultraviolet radiation (UV cure), orperforming any other suitable cure process to fully harden encapsulationmaterial 232.

FIGS. 16-19, discussed below, exemplify operations that can occur inaccordance with step 188 (FIG. 7) of wafer level packaging process 170during which redistribution layers are formed over panel assembly 238.

FIG. 16 shows a partial side view of panel assembly 238 at a subsequentstage 240 of processing in accordance with step 188 of wafer levelpackaging process 170. At stage 240, a back side 242 of panel assembly238 may be attached to a back-side support carrier 244 using, forexample, double-sided silicon tape 204. Accordingly, a surface 234 ofsemiconductor wafer 212 and active side 222 of electronic devices 220having electrical contacts 248 are exposed. In some processes, surface234 of semiconductor wafer 212 and active side 222 of electronic devices220 may be cleaned to remove possible residue from electrical contacts248.

FIG. 17 shows a partial side view of panel assembly 238 from FIG. 16 ata subsequent stage 250 of processing in accordance with step 188 (FIG.7) of wafer level packaging process 170. At stage 250, a dielectriclayer 252 may be applied over surface 234 of semiconductor wafer 212 andactive side 222 of electronic devices 220 of panel assembly 238 using,for example, a spin coat dielectric deposition process, a dispenseprocess, an screen printing process, and the like. Openings 254 may beformed in dielectric layer 252 using a suitable etch process in order toexpose electrical contacts 248 from dielectric layer 252. Thereafter,dielectric layer 252 may undergo a suitable cure process.

FIG. 18 shows a partial side view of panel assembly 238 from FIG. 17 ata subsequent stage 256 of processing in accordance with step 188 (FIG.7) of wafer level packaging process 170. At stage 256, openings 254 maybe suitably cleaned, a seed layer for a first conductive layer may beformed by a sputtering process, and a resist pattern for the firstconductive layer may be formed over the seed layer in accordance withknown methodologies. Thereafter, a first conductive layer 258 may beformed over dielectric layer 252 using, for example, an electroplatingprocess. The resist material is suitably removed so that conductiveinterconnects 260 having conductive traces 262 and conductive vias 264in electrical communication with electrical contacts 248 remain.

FIG. 19 shows a partial side view of panel assembly 238 from FIG. 18 ata subsequent stage 266 of processing in accordance with step 188 ofwafer level packaging process 170. At stage 266, another dielectriclayer 268 may be applied over conductive interconnects 260 of firstconductive layer 258 and any exposed regions of dielectric layer 252using, for example, a spin coat dielectric deposition process. Again,openings 270 may be formed in dielectric layer 268 using a suitable etchprocess in order to expose traces 262 of conductive interconnects 260 atpredetermined locations from dielectric layer 268. Thereafter,dielectric layer 268 may undergo a suitable cure process.

Only a single conductive layer 258 and two dielectric layers 252, 268are described in connection with FIGS. 17-19. However, it should beunderstood that the operations demonstrated in FIGS. 17-19 may berepeated to obtain a predetermined layered arrangement and geometry ofdielectric layers and conductive interconnects.

FIG. 20 shows a partial side view of panel assembly 238 at a subsequentstage 272 of processing in accordance with step 190 of wafer levelpackaging process 170. At stage 272, conductive elements in the form of,for example, solder balls 274 are formed at opening 270 of the outermostdielectric layer 268 and are suitably electrically connected withconductive interconnects 260 to provide input/output capability forelectrical contacts 248 on electronic devices 220. Solder balls 274 maybe formed using a solder mask application process and by a solder printor a sphere attach process. Thereafter, panel assembly 238 may bedetached from back-side support carrier 244, cleaned, mounted, and sawnor diced along scribe lines 276 into multiple integrated electronicpackages 278 in accordance with step 192 of wafer level packagingprocess 170.

It is to be understood that certain ones of the process blocks depictedin FIG. 7 and demonstrated in connection with FIGS. 8-20 may beperformed in parallel with each other or with performing otherprocesses. In addition, it is to be understood that the particularordering of the process blocks depicted in FIG. 7 may be modified, whileachieving substantially the same result. Accordingly, such modificationsare intended to be included within the scope of the inventive subjectmatter. In addition, although package configurations are described inconjunction with FIGS. 1-4 above, embodiments may be implemented inpackages having other architectures, as well. These and other variationsare intended to be included within the scope of the inventive subjectmatter.

For simplicity and clarity of illustration, the drawing figuresillustrate the general manner of construction. Descriptions and detailsof well-known features and techniques may be omitted to avoidunnecessarily obscuring the invention. Additionally, elements in thedrawings figures are not necessarily drawn to scale. For example, thedimensions of some of the elements or regions in some of the figures maybe exaggerated relative to other elements or regions of the same orother figures to help improve understanding of embodiments of theinvention. Furthermore, different elements may be illustrated variouslyto include hatching, stippling, or some other pattern in order to moreclearly distinguish the elements from one another.

The terms “first,” “second,” “third,” “fourth” and the like in thedescription and the claims, if any, may be used for distinguishingbetween similar elements and not necessarily for describing a particularsequential or chronological order. It is to be understood that the termsso used are interchangeable under appropriate circumstances such thatthe embodiments of the invention described herein are, for example,capable of operation or use in sequences other than those illustrated orotherwise described herein. Furthermore, the terms “comprise,”“include,” “have” and any variations thereof, are intended to covernon-exclusive inclusions, such that a process, method, article, orapparatus that comprises a list of elements is not necessarily limitedto those elements, but may include other elements not expressly listedor inherent to such process, method, article, or apparatus. The terms“left,” “right,” “in,” “out,” “front,” “back,” “up,” “down,” “top,”“bottom,” “over,” “under,” “above,” “below,” and the like in thedescription and the claims, if any, are used for describing relativepositions and not necessarily for describing permanent positions inspace. It is to be understood that the embodiments of the inventiondescribed herein may be used, for example, in other orientations thanthose illustrated or otherwise described herein. The term “coupled,” asused herein, is defined as directly or indirectly connected in anelectrical or non-electrical manner.

Various embodiments of a method of wafer level packaging and integratedelectronic packages produced via the wafer level packaging methodologyhave been described. A panel assembly of electronic devices is formedthat includes an embedded semiconductor wafer. The embeddedsemiconductor wafer serves to limit warpage of the panel assembly duringencapsulation relative to a panel assembly made of mold compound inorder to increase package yield and decrease manufacturing complexityduring a subsequent build up process. Furthermore, the incorporation ofa semiconductor wafer, such as a silicon wafer, can reduce materialcosts as well as manufacturing and tooling costs, and can reduce therate of wear of the saw blade during package singulation due to thesoftness of the semiconductor wafer relative to the use of a copper EGP.Additionally, the implementation of an embedded semiconductor wafer inthe panel assembly can achieve reduced thermal expansion, hence betterdie drift performance, relative to the use of a copper EGP. And stillfurther, the semiconductor wafer embedded in the panel assembly can beused as a platform for a redistribution process and/or for formingthrough silicon vias.

While the principles of the inventive subject matter have been describedabove in connection with specific apparatus and methods, it is to beclearly understood that this description is made only by way of exampleand not as a limitation on the scope of the inventive subject matter.Further, the phraseology or terminology employed herein is for thepurpose of description and not of limitation.

The foregoing description of specific embodiments reveals the generalnature of the inventive subject matter sufficiently so that others can,by applying current knowledge, readily modify and/or adapt it forvarious applications without departing from the general concept.Therefore, such adaptations and modifications are within the meaning andrange of equivalents of the disclosed embodiments. The inventive subjectmatter embraces all such alternatives, modifications, equivalents, andvariations as fall within the spirit and broad scope of the appendedclaims.

What is claimed is:
 1. A method comprising: providing a platformstructure having a plurality of cavities extending through a thicknessof said platform structure, said cavities being sized to acceptelectronic devices, wherein said platform structure comprises asemiconductor material; mounting said platform structure to a temporarysupport; placing said electronic devices in said cavities of saidplatform structure; encapsulating said platform structure and saidelectronic devices in an encapsulation material to produce a panelassembly containing said electronic devices and said platform structure,wherein following said encapsulating, said method further comprises:removing said panel assembly from said temporary support to expose anactive side of each of said electronic devices at which electricalcontacts are located; applying at least one insulating layer over saidactive side of said each of said electronic devices; forming openings insaid at least one insulating layer to expose at least some of saidelectrical contacts on said active side of said each of said electronicdevices; providing conductive interconnects over said at least oneinsulating layer and extending through at least some of said openings insaid at least one insulating layer; separating said panel assembly intoa plurality of integrated electronic packages following said providingsaid conductive interconnects, wherein for each of said integratedelectronic packages, said separating exposes one of said conductiveinterconnects at a side wall of said each integrated electronic package;and for said each of said integrated electronic packages, forming aconductive trace extending along said side wall, said conductive tracebeing in electrical communication with said one of said conductiveinterconnects.
 2. The method of claim 1 wherein said providing comprisesproviding said platform structure with said cavities having acurvilinear shape.
 3. The method of claim 1 wherein said providingcomprises forming said platform structure from said semiconductormaterial having a first coefficient of thermal expansion (CTE) that isless than a second CTE of said encapsulation material.
 4. The method ofclaim 1 wherein said providing comprises forming said platform structurefrom a material having a particle size of no greater than five microns.5. The method of claim 1 wherein: said placing comprises placing saidelectronic devices in said cavities so that gaps are located betweendevice edges of said electronic devices and cavity edges of saidcavities in said platform structure; and said encapsulating comprisesproviding said encapsulation material in said gaps.
 6. The method ofclaim 1 wherein: said mounting comprises mounting said platformstructure with a first surface of said platform structure facing saidtemporary support; and said method further comprises exposing a secondsurface of said platform structure from said encapsulation material,said second surface opposing said first surface.
 7. The method of claim1 further comprising forming conductive vias extending through saidplatform structure.
 8. The method of claim 1 wherein said integratedelectronic packages are first integrated electronic packages and foreach of said first integrated electronic packages, said method furthercomprises: coupling a second integrated electronic package to one of atop exterior surface and a bottom exterior surface of said firstintegrated electronic package; and electrically interconnecting saidconductive trace extending along said side wall of said first integratedelectronic package with a second electronic device of said secondintegrated electronic package.
 9. The method of claim 1 wherein saidseparating occurs through said platform structure so that a portion ofsaid platform structure is exposed at said side wall of each of saidintegrated electronic packages.
 10. A method comprising: providing aplatform structure having a plurality of cavities extending through athickness of said platform structure, said cavities being sized toaccept electronic devices, wherein said platform structure comprises asemiconductor material; forming conductive vias extending through saidplatform structure; mounting said platform structure to a temporarysupport; placing said electronic devices in said cavities of saidplatform structure; encapsulating said platform structure and saidelectronic devices in an encapsulation material to produce a panelassembly containing said electronic devices, said platform structure,and said conductive vias; and separating said panel assembly into aplurality of integrated electronic packages following saidencapsulating, said separating occurring through said platform structureso that a portion of said platform structure is exposed at opposing sidewalls of each of said integrated electronic packages, wherein prior tosaid separating, said method further comprises: removing said panelassembly from said temporary support to expose an active side of each ofsaid electronic devices at which electrical contacts are located;applying at least one insulating layer over said active side of saideach of said electronic devices and over a non-cavity area of saidplatform structure surrounding said active side of said each of saidelectronic devices; forming openings in said at least one insulatinglayer to expose at least some of said electrical contacts on said activeside of said each of said electronic devices; forming said openings insaid at least one insulating layer overlying said non-cavity area ofsaid platform structure; and providing conductive interconnects oversaid at least one insulating layer and extending through at least someof said openings in said at least one insulating layer.
 11. A methodcomprising: providing a platform structure having a plurality ofcavities extending through a thickness of said platform structure, saidcavities being sized to accept electronic devices, wherein said platformstructure comprises a semiconductor material; forming conductive viasextending through said platform structure; mounting said platformstructure to a temporary support; placing said electronic devices insaid cavities of said platform structure; encapsulating said platformstructure and said electronic devices in an encapsulation material toproduce a panel assembly containing said electronic devices, saidplatform structure, and said conductive vias, wherein following saidencapsulating, said method further comprises: removing said panelassembly from said temporary support to expose an active side of each ofsaid electronic devices at which electrical contacts are located;applying at least one insulating layer over said active side of saideach of said electronic devices; forming openings in said at least oneinsulating layer to expose at least some of said electrical contacts onsaid active side of said each of said electronic devices; and providingconductive interconnects over said at least one insulating layer andextending through at least some of said openings in said at least oneinsulating layers; separating said panel assembly into a plurality ofintegrated electronic packages following said encapsulating, saidseparating occurring through said platform structure so that a portionof said platform structure is exposed at opposing side walls of each ofsaid integrated electronic packages, wherein following said providingsaid conductive interconnects, said separating exposes one of saidconductive interconnects at a side wall of said each integratedelectronic package; and for said each of said integrated electronicpackages, forming a conductive trace extending over said portion of saidplatform structure at said side wall, said conductive trace being inelectrical communication with said one of said conductive interconnects.